Patent US5718827A successfully refreshed from Google Patents.
US5718827A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Paper filter for removing metal cations
Assignee: Little Rapids Corp
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Filing: 1995-03-29
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Granted: 1998-02-17
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Expires: 2015-03-29
Abstract
Abstract Disposable paper filters suitable for removal of contaminants from fluids such as water or air are disclosed. Specific embodiments include single-ply and multi-ply filters in which metal removal additives and/or halogen and organic contaminant removal additives have been distributed during the manufacturing process. Special manufacturing methods for producing such composite filters are also described.
Inventors
- 👤 Theodore B. Rydell
- 👤 Joseph D. Wahlquist
- 👤 Gerald W. Tumanic
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 06:26
CPC Classifications
B; B01; B01J; B01J20/00; B01J20/28; B01J20/28014; B01J20/28033; B01D; B01D39/00; B01D39/14; B01D39/16; B01D39/18; B01J20/28028; B01J20/28054; B01J20/28078; B01J20/28088; D; D21; D21H; D21H17/00; D21H17/63; D21H17/67; D21H17/68; D21H27/00; D21H27/08
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
64 words
A paper filter ply comprising a porous sheet made of unbleached Kraft pulp suitable for removing dissolved metal cations, said paper filter ply having a Kappa number of between about 10 and about 50, said paper filter ply also having a pore size distribution of between about 0.5 microns and about 50 microns and a Canadian Standard Freeness of at least about 400 ml.
Claim 2
Dependent Claim
64 words
A paper filter ply comprising a porous sheet made of unbleached Kraft pulp suitable for removing dissolved metal cations, said paper filter ply having a Kappa number of between about 10 and about 50, said paper filter ply also having a pore size distribution of between about 0.5 microns and about 50 microns and a Canadian Standard Freeness of at least about 400 ml.
Claim 3
Dependent Claim
21 words
The paper filter ply of claim 1 having a net electronegative characteristic permitting removal of dissolved metal cations from drinking water.
Claim 4
Dependent Claim
11 words
The filter ply of claim 1, further comprising a flavoring agent.
Claim 5
Dependent Claim
28 words
The filter ply of claim 1, wherein said filter ply is formed into a roll with periodic perforations, allowing individual filters to be torn off for single-use applications.
References Cited (Backward Citations)
GB870975A
Cited
US3246767A
Cited
US3327859A
Cited
US3561602A
Cited
US3862901A
Cited
US4007113A
Cited
US3965008A
Cited
US4054515A
Cited
US4859340A
Cited
US4094234A
Cited
US4098177A
Cited
US4119543A
Cited
US4075107A
Cited
US4133754A
Cited
US4039444A
Cited
US4094779A
Cited
US4287057A
Cited
US4594158A
Cited
US4455237A
Cited
US4505823A
Cited
GB2145011A
Cited
US4564452A
Cited
US4986913A
Cited
US4741828A
Cited
US4707263A
Cited
US4696744A
Cited
US4759844A
Cited
US5064534A
Cited
US4749481A
Cited
US4882055A
Cited
US4800018A
Cited
US4747955A
Cited
US4863601A
Cited
US4787973A
Cited
US4816149A
Cited
US4975292A
Cited
US4988440A
Cited
US5032224A
Cited
EP0402661A1
Cited
US5186830A
Cited
US5486468A
Cited
US5096721A
Cited
US5192571A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-02-16 | 2001-08-18 | 2002-02-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-02-16 | 2005-08-18 | 2006-02-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-02-16 | 2009-08-18 | 2010-02-17 | $7700.00 | Window Closed / Lapsed |